Those who knew Paddock -- including his brother -- have expressed confusion over how someone who did not seem at all out of the ordinary could have committed such an act of violence. However, as officials continue to search his hotel room and homes, and piece together what led up to the shooting, they're discovering a disturbing picture.

"He was a wealthy guy playing video poker ... on cruises," Paddock's brother, Eric Paddock, tells CNN; Stephen Paddock's brother also notes that Paddock played $100-a-hand poker and could "afford anything he wanted." According to NBC, Paddock gambled "more than $10,000 a day -- and in some cases amounts greater than $20,000 and $30,000 -- at Las Vegas casinos ..."

Paddock lived in a retirement community in Mesquite, Nev., about 80 miles northeast of Las Vegas; he previously lived in Orlando, Fla. Paddock had been married in the past, his brother says, and was living with his current girlfriend, Marilou Danley.

Paddock was college educated and started his own business before retiring to outside of Las Vegas, where he purchased a $369,000 home in 2015. According to Fox News, Paddock worked for a predecessor of Lockheed Martin in the 1980s; 8NewsNow shared a statement from the company, saying that they are "cooperating with authorities to answer questions they may have about Mr. Paddock and his time with the company."

More a dozen guns were discovered in Paddock's hotel room at Mandalay Bay -- which he checked into on Sept. 28 and which was located on the 32nd floor -- including a .223 caliber rifle and a .308 caliber rifle. According to CNN, "suspicion, based on initial reports, is that any of the rifles used were altered to function as an automatic weapon," and that the guns were obtained legally. However, in an interview with CBS, Eric Paddock expresses shock, stating that his brother was "not an avid gun guy at all."

"Where the hell did he get automatic weapons?" Eric Paddock asks. "He has no military background."

Country Stars Respond Following Route 91 Harvest Festival Shooting

In addition to the firearms in Paddock's hotel room, authorities thousands of rounds of ammunition, as well as explosives and another 18 guns at Paddock's home in Mesquite. He also owned a home in northern Nevada; police have not yet revealed what, if anything was found there.

According to Eric Paddock, his and Stephen Paddock's father was a bank robber, Benjamin Hoskins Paddock, who was on the FBI's most-wanted list from 1969 until 1977. Eric Paddock says that his father died a few years ago, and that his family never really knew him. The last time that Eric Paddock heard from his brother was in a text message, inquiring about their mother, who had lost power in Hurricane Irma.

"He was my brother, and it's like an asteroid fell out of the sky," Eric Paddock says, expressing shock over the mass murder perpetrated by his brother.